E(t) ¼ E(t À dt) + (ΔE) * dt
INIT E ¼ .95 {Percentage of Foilage Cover}
INFLOWS:
ΔE ¼ RE * E * (1ÀE) À P * B * E^2/S {Change in Percentage of Foilage Cover per
Time Period}
S(t) ¼ S(t À dt) + (ΔS) * dt
INIT S ¼ 2.5 {Habitat Density}
INFLOWS:
ΔS ¼ RS * S * (1 À S/KS/E) {Habitat Density Change per Time Period}
C ¼ 1
F ¼ R_1 * (1ÀX/Q)
G ¼ X/(1+X^2)
GR ¼ 2 {Spruce Budworm per Unit Area per Spruce Budworm per Unit Area per
Time Period}
K ¼ 1
K1 ¼ 0.1
KS ¼ 2.5
P ¼ 0.01
Q ¼ K/K1
R ¼ GR * K1 * S/C
RE ¼ 2 {Change in Percentage of Foilage Cover per Percentage Foilage Cover
Time Period}
RS ¼ 3 {Habitat Density Change per Habitat Density Change per Time Period}
R_1 ¼ GR * K1 * KS/C
X ¼ TIME
Reference
1. Beltrami E (1987) Mathematics for dynamic modeling. Academic Press, Boston
Reference
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